FIG. 4.

Hybridization of ³²P-labeled cDNA with ORF-specific DNA of pRm1132f. cDNA probes prepared with ORF-specific oligonucleotide primers (see Table 2), total RNA from S. meliloti 1132, and reverse transcriptase were hybridized to ORF-specific DNA electrophoresed on agarose gels and blotted onto nylon filters. ORF-specific DNAs are numbered as indicated. Three separate hybridizations were carried out with cDNA probes derived from ORF1 (left panel), ORFs 2 to 4 (middle panel), and ORFs 5, 7, and 8 (right panel).